Optical microdisk array fabrication with sol-gel techniques was investigated. The characteristics of the microdisk array doped with Rhodamine B were studied with pulsed laser excitation. The whispering-gallery mode (WGM) emission spectra were observed. The WGM is very sensitive to the external circumstance under certain condition. The possible application of microdisk array as sensor also was investigated. We found the amplified spontaneous emission produced from microdisk array is very sensitive to the trace of material detected. The result showed that the microdisk as a kind of sensor has potential application in integrated optics.